Synthetic Estimators Using Auxiliary Information in Small Domains

An unbiased estimate is obtained from a sample survey for a large area; when this estimate is used to derive estimates for sub areas on the assumption that the small areas have the same characteristics as larger area, we identify these estimates as synthetic estimators¿. One of the simplest estimators arises from the assumption that the small area mean is equal to the larger area mean. This leads to the simple synthetic estimator under simple random sampling or stratified random sampling or post stratified sampling as the case may be. Synthetic estimation may also be based on auxiliary data. Such estimators are, for example, ratio-synthetic, product -synthetic and regression - synthetic estimators.